Accordingly, a practical interpretation of the objective of fracturing a horizontal well is to create a system whose long-term performance is identical to that of a single effective, or total, fracture of length equal to the spacing between the outermost fractures (Raghavan et al., 1997, and Chen and Raghavan, 1997). Figure 1.2 provides a sketch of this interpretation. With this interpretation, performances of fractured horizontal wells can be correlated in terms of an effective fracture conductivity and effective fracture half-length. The conductivity of this effective fracture depends on the permeability of the reservoir and the number, distance between, and conductivities of the individual hydraulic fractures.